Method for manufacturing printed circuit board

ABSTRACT

Disclosed herein is a method for manufacturing a printed circuit board for forming a solder resist of an outermost layer having a step structure by performing laser machining or exposing and developing processes.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2012-0085270, filed on Aug. 3, 2012, entitled “Method ForManufacturing of Printed Circuit Board”, which is hereby incorporated byreference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a method for manufacturing a printedcircuit board.

2. Description of the Related Art

In addition to Patent Document 1, a printed circuit board has beenvariously used for several applications such various electronicproducts, in particular, mobile electronic products, and the like.

As applications of the printed circuit board have been expanded, astructure of the printed circuit board has been diversified.

For example, due to a demand for thinness and miniaturization of mobileelectronic products, packaging companies tend to enhance the thinness ofa semiconductor package substrate so as to increase a packaging densityand reduce a thickness of a package.

RELATED ART DOCUMENT Patent Document (Patent Document 1) US 2008-0053688A1 SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a method formanufacturing a printed circuit board for forming a solder resist of anoutermost layer having a step structure.

According to a preferred embodiment of the present invention, there isprovided a method for manufacturing a printed circuit board, including:preparing a base substrate on which a circuit layer segmented into afirst surface treating area and a second surface treating area isformed; forming a solder resist layer on the base substrate, includingthe circuit layer; forming a first open part of the first surfacetreating area and a first open part of the second surface treating areaby performing exposing and developing processes on solder resist layerscorresponding to the first surface treating area and the second surfacetreating area; forming a step open part of the first surface treatingarea exposing the circuit layer of the first surface treating area byperforming the exposing and developing processes of the first open partof the first surface treating area; forming the first surface treatinglayer on the exposed circuit layer of the first surface treating area;forming a second open part of the second surface area by performinglaser machining on the first open part of the second surface treatingarea to expose the circuit layer of the second surface treating area;and forming the second surface treating layer on the exposed circuitlayer of the second surface treating area, wherein the solder resistlayer is formed with a step shape corresponding to the step open part ofthe first surface treating area.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the solder resist layer and before theforming of the first open part of the first surface treating area andthe first open part of the second surface treating area, removing thesolder resist layer based on a thickness direction of a substrate byperforming the exposing and developing processes on the overall surfaceof an upper portion of the solder resist layer to arbitrarily reduce athickness thereof.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the first surface treating layer andbefore the forming of the second open part of the second surfacetreating area, forming a mask layer having an open part corresponding tothe second open part of the second surface treating area on the solderresist layer.

The mask layer may be formed of a dry film.

In the forming of the step open part of the first surface treating area,the step open part of the first surface treating area may be formed soas to expose an upper surface and a side of the circuit layer of thefirst surface treating area.

In the forming of the second open part of the second surface treatingarea, the second open part of the second surface treating area may beformed to be equal to a size of the first open part of the secondsurface treating area based on a length direction of the substrate.

In the forming of the second open part of the second surface treatingarea, the second open part of the second surface treating area may beformed to be smaller than a size of the first open part of the secondsurface treating area based on a length direction of the substrate.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the second opening part of the secondsurface treating area and before the forming of the second surfacetreating layer on the exposed circuit layer of the second surfacetreating area, performing a desmear process on the first open part andthe second open part of the second surface treating area.

According to another preferred embodiment of the present invention,there is provided a method for manufacturing a printed circuit board,including: preparing a base substrate on which a circuit layer segmentedinto a first surface treating area and a second surface treating area isformed; forming a solder resist layer on the base substrate, includingthe circuit layer; forming a first open part of the first surfacetreating area and a first open part of the second surface treating areaby performing laser machining on solder resist layers corresponding tothe first surface treating area and the second surface treating area;forming a step open part of the first surface treating area exposing thecircuit layer of the first surface treating area by performing the lasermachining on the first open part of the first surface treating area;forming the first surface treating layer on the exposed circuit layer ofthe first surface treating area; forming a second open part of thesecond surface treating area by performing laser machining on the firstopen part of the second surface treating area to expose the circuitlayer of the second surface treating area; and forming the secondsurface treating layer on the exposed circuit layer of the secondsurface treating area; wherein the solder resist layer is formed with astep shape corresponding to the step open part of the first surfacetreating area.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the solder resist layer and before theforming of the first open part of the first surface treating area andthe first open part of the second surface treating area, removing thesolder resist layer based on a thickness direction of a substrate byperforming the exposing and developing processes on the overall surfaceof an upper portion of the solder resist layer to arbitrarily reduce athickness thereof.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the solder resist layer and before theforming of the first open part of the first surface treating area andthe first open part of the second surface treating area, removing thesolder resist layer based on a thickness direction of a substrate byperforming the laser machining on the overall surface of an upperportion of the solder resist layer to arbitrarily reduce a thicknessthereof.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the first surface treating layer andbefore the forming of the second open part of the second surfacetreating area, forming a mask layer having an open part corresponding tothe second open part of the second surface treating area on the solderresist layer.

The mask layer may be formed of a dry film.

In the forming of the step open part of the first surface treating area,the step open part of the first surface treating area may be formed soas to expose an upper surface and a side of the circuit layer of thefirst surface treating area.

In the forming of the second open part of the second surface treatingarea, the second open part of the second surface treating area may beformed to be equal to a size of the first open part of the secondsurface treating area based on a length direction of the substrate.

In the forming of the second open part of the second surface treatingarea, the second open part of the second surface treating area may beformed to be smaller than a size of the first open part of the secondsurface treating area based on a length direction of the substrate.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the step opening part of the first surfacetreating area and before the forming of the first surface treating layeron the exposed circuit layer of the first surface treating area,performing a desmear process on the step open part of the first surfacetreating area.

The method for manufacturing a printed circuit board may furtherinclude: after the forming of the second opening part of the secondsurface treating area and before the forming of the second surfacetreating layer on the exposed circuit layer of the second surfacetreating area, performing a desmear process on the first open part andthe second open part of the second surface treating area.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIGS. 1 to 7 are process cross-sectional views for describing a methodfor manufacturing a printed circuit board according to an exemplaryembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The objects, features and advantages of the present invention will bemore clearly understood from the following detailed description of thepreferred embodiments taken in conjunction with the accompanyingdrawings. Throughout the accompanying drawings, the same referencenumerals are used to designate the same or similar components, andredundant descriptions thereof are omitted. Further, in the followingdescription, the terms “first”, “second”, “one side”, “the other side”and the like are used to differentiate a certain component from othercomponents, but the configuration of such components should not beconstrued to be limited by the terms. Further, in the description of thepresent invention, when it is determined that the detailed descriptionof the related art would obscure the gist of the present invention, thedescription thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the attached drawings.

Method for Manufacturing Printed Circuit Board

FIGS. 1 to 7 are process cross-sectional views for describing a methodfor manufacturing a printed circuit board according to an exemplaryembodiment of the present invention.

First, as shown in FIG. 1, a base substrate 110 on which a circuit layer120 segmented into a first surface treating area and a second surfacetreating area is formed may be prepared.

The base substrate 110 may be a printed circuit board on which a generalinsulating layer used as a core substrate in a printed circuit boardfield or a circuit including a connection pad of one or more layer on aninsulating layer is formed.

As the insulating layer, a resin insulating layer may be used As theresin insulating layer, thermosetting resin such as epoxy resin,thermoplastic resin such as polyimide, resin having reinforcingmaterials such as a glass fiber or an inorganic filler impregnatedthereinto, for example, prepreg, and the like, may be used In addition,thermosetting resin and/or photocurable resin, and the like, may beused, but the exemplary embodiment of the present invention are notparticularly limited thereto.

A solder ball as an external connection terminal is formed on theconnection pad by a subsequent process and a semiconductor device orexternal components and an inner-layer circuit are electricallyconnected by the solder ball.

The circuit including the connection pad may be applied without beinglimited if a conductive metal for a circuit may be used in the printedcircuit board field. Typically, copper may be used in the printedcircuit board.

Next, as shown in FIG. 1, a solder resist layer 130 may be formed on thebase substrate 110, including the circuit layer 120.

The solder resist layer 130 serves as a protective layer protecting anoutermost layer circuit and is formed to implement electrical insulationand may be formed with an open part so as to expose a connection pad atan outermost layer. As known to those skilled in the art, the solderresist layer 130 may be formed of for example, photocurable resin,thermosetting resin, a complex material of the photocurable resin andthe thermosetting resin, and the like, but the exemplary embodiment ofthe present invention is not particularly limited thereto.

Next, although not shown, the overall surface of the upper portion ofthe solder resist layer 130 is subjected to the exposing and developingprocesses to remove the solder resist layer 130 based on a thicknessdirection of the substrate, thereby making it possible to arbitrarilyreduce a thickness thereof and omitting the corresponding processesaccording to the operator demand.

Meanwhile, the overall surface of the upper portion of the solder resistlayer 130 is subjected to the laser machining to remove the solderresist layer 130 based on the thickness direction of the substrate,thereby making it possible to arbitrarily reduce the thickness thereof.

The process of reducing the thickness of the foregoing solder resistlayer 130 is to improve the convenience of the laser machining that isprogressed later.

Next, as shown in FIG. 1, the solder resist layers 130 corresponding tothe first surface treating area and the second surface treating area aresubjected to the exposing and developing processes to form a first openpart 131 on the first surface treating area and a first open part 132 ona second surface treating area.

Meanwhile, the solder resist layer 130 corresponding to the firstsurface treating area and the second surface treating area may besubjected to the laser machining to form the first open part 131 on thefirst surface treating area and the first open part 132 on the secondsurface treating area.

Next, as shown in FIG. 2, the first open part (131 of FIG. 1) on thefirst surface treating area may be subjected to the exposing anddeveloping process to form a step open part 133 on the first surfacetreating area exposing the circuit layer 120 of the first surfacetreating area.

In this case, as shown in FIG. 7, it is possible to form the step openpart 133 on the first surface treating area so as to expose (area A ofFIG. 7) the upper surface and side of the circuit layer 120 of the firstsurface treating area.

Meanwhile, the first open part (131 of FIG. 1) on the first surfacetreating area may be subjected to the laser machining to form the stepopen part 133 on the first surface treating area exposing the circuitlayer 120 of the first surface treating area.

Next, the step open part 133 on the first surface treating area may besubjected to a desmear process.

Next, as shown in FIG. 3, a first surface treating layer 150 may beformed on the exposed circuit layer 120 of the first surface treatingarea.

In this case, for the convenience of explanation, FIG. 3 shows that bothof the first surface treating layer 150 and a mask layer 140 are formed,but it is apparent that the surface treating layer 150 is first formedand then, the mask layer 140 is formed through a post-process.

The first surface treating layer 150 is not particularly limited to ifknown to those skilled in the art and may be formed, for example, byelectro gold plating, immersion gold plating, Organic SolderabilityPreservative (OSP), immersion tin plating, immersion silver plating,electroless nickel and immersion gold (ENIG), Direct Immersion Gold(DIG) plating, Hot Air Solder Leveling (HASL), Electroless NickelElectroless Palladium Immersion Gold (ENEPIG), or Electroless PalladiumImmersion Gold (EPIG), and the like.

Next, as shown in FIGS. 3 and 4, the mask layer 140 having the open part141 corresponding to a second open part of the second surface treatingarea may be formed on the solder resist layer 130.

In this case, the mask layer may be formed of a dry film.

Next, as shown in FIG. 5, the first open part (132 of FIG. 2) on thesecond surface treating area may be subjected to the laser machining toexpose the circuit layer 120 of the second surface treating area,thereby forming the second open part 134 on the second surface treatingarea.

In this case, as shown in FIG. 5, the second open part 134 on the secondsurface treating area may be formed to be equal to the size of the firstopen part 132 on the second surface treating area based on a lengthdirection of the substrate.

However, the same herein means substantially the same size inconsideration of a manufacturing error, a measuring error of thethickness having exactly the same dimension in a mathematical meaning.

Meanwhile, as shown in FIG. 6, the second open part 134 on the secondsurface treating area may be formed so as to be smaller than the size ofthe first open part 132 on the second surface treating area based on alength direction of the substrate.

The size of the open part may be variously changed according to anoperator demand in addition to the foregoing structure.

Next, as shown in FIG. 5, the first open part 132 and the second openpart 134 on the second surface treating area may be subjected to thedesmear process.

In this case, as a result of performing the desmear process, as shown inFIG. 5, a desmear treating layer 135 may be formed.

Next, as shown in FIG. 5, a second surface treating layer 160 may beformed on the exposed circuit layer 120 of the second surface treatingarea.

The second surface treating layer 160 is not particularly limited to ifknown to those skilled in the art and may be formed, for example, byelectro gold plating, immersion gold plating, Organic SolderabilityPreservative (OSP), immersion tin plating, immersion silver plating,electroless nickel and immersion gold (ENIG), Direct Immersion Gold(DIG) plating, Hot Air Solder Leveling (HASL), Electroless NickelElectroless Palladium Immersion Gold (ENEPIG), or Electroless PalladiumImmersion Gold (EPIG), and the like.

In this case, the first surface treating layer 150 and the secondsurface treating layer 160 may be formed of different materials.

The solder resist layer 130 may be formed with a step shapecorresponding to the step open part 133 on the first surface treatingarea by the foregoing manufacturing process.

In addition, as shown in FIG. 6, the solder resist layer 130corresponding to the second surface treating area may also be formedwith the step structure.

A multi-stage multi structure having the step structure according to thepreferred embodiment of the present invention is applied to the printedcircuit board for the package on package (PoP) and thus, can be easilybonded with the semiconductor device or the electronic parts.

The method for manufacturing a printed circuit board according to thepreferred embodiments of the present invention can provide the printedcircuit board for the package on package capable of easily mounting thesemiconductor device by forming the solder resist having the stepstructure using the exposing and developing processes or the lasermachining.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, they are for specificallyexplaining the present invention. Therefore, those skilled in the artwill appreciate that various modifications and alteration are possible,without departing from the scope and spirit of the invention asdisclosed in the accompanying claims.

Accordingly, such modifications and alterations should also beunderstood to fall within the scope of the present invention. A specificprotective scope of the present invention could be defined byaccompanying claims.

What is claimed is:
 1. A method for manufacturing a printed circuitboard, comprising: preparing a base substrate on which a circuit layersegmented into a first surface treating area and a second surfacetreating area is formed; forming a solder resist layer on the basesubstrate, including the circuit layer; forming a first open part of thefirst surface treating area and a first open part of the second surfacetreating area by performing exposing and developing processes on solderresist layers corresponding to the first surface treating area and thesecond surface treating area; forming a step open part of the firstsurface treating area exposing the circuit layer of the first surfacetreating area by performing the exposing and developing processes on thefirst open part of the first surface treating area; forming the firstsurface treating layer on the exposed circuit layer of the first surfacetreating area; forming a second open part of the second surface treatingarea by performing laser machining on the first open part of the secondsurface treating area to expose the circuit layer of the second surfacetreating area; and forming the second surface treating layer on theexposed circuit layer of the second surface treating area, wherein thesolder resist layer is formed with a step shape corresponding to thestep open part of the first surface treating area.
 2. The method as setforth in claim 1, further comprising: after the forming of the solderresist layer and before the forming of the first open part of the firstsurface treating area and the first open part of the second surfacetreating area, removing the solder resist layer based on a thicknessdirection of a substrate by performing the exposing and developingprocesses on the overall surface of an upper portion of the solderresist layer to arbitrarily reduce a thickness thereof.
 3. The method asset forth in claim 1, further comprising: after the forming of the firstsurface treating layer and before the forming of the second open part ofthe second surface treating area, forming a mask layer having an openpart corresponding to the second open part of the second surfacetreating area on the solder resist layer.
 4. The method as set forth inclaim 3, wherein the mask layer is formed of a dry film.
 5. The methodas set forth in claim 1, wherein in the forming of the step open part ofthe first surface treating area, the step open part of the first surfacetreating area is formed so as to expose an upper surface and a side ofthe circuit layer of the first surface treating area.
 6. The method asset forth in claim 1, wherein in the forming of the second open part ofthe second surface treating area, the second open part of the secondsurface treating area is formed to be equal to a size of the first openpart of the second surface treating area based on a length direction ofthe substrate.
 7. The method as set forth in claim 1, wherein in theforming of the second open part of the second surface treating area, thesecond open part of the second surface treating area is formed to besmaller than a size of the first open part of the second surfacetreating area based on a length direction of the substrate.
 8. Themethod as set forth in claim 1, further comprising: after the forming ofthe second opening part of the second surface treating area and beforethe forming of the second surface treating layer on the exposed circuitlayer of the second surface treating area, performing a desmear processon the first open part and the second open part of the second surfacetreating area.
 9. A method for manufacturing a printed circuit board,comprising: preparing a base substrate on which a circuit layersegmented into a first surface treating area and a second surfacetreating area is formed; forming a solder resist layer on the basesubstrate, including the circuit layer; forming a first open part of thefirst surface treating area and a first open part of the second surfacetreating area by performing laser machining on solder resist layerscorresponding to the first surface treating area and the second surfacetreating area; forming a step open part of the first surface treatingarea exposing the circuit layer of the first surface treating area byperforming the laser machining on the first open part of the firstsurface treating area; forming the first surface treating layer on theexposed circuit layer of the first surface treating area; forming asecond open part of the second surface treating area by performing lasermachining on the first open part of the second surface treating area toexpose the circuit layer of the second surface treating area; andforming the second surface treating layer on the exposed circuit layerof the second surface treating area, wherein the solder resist layer isformed with a step shape corresponding to the step open part of thefirst surface treating area.
 10. The method as set forth in claim 9,further comprising: after the forming of the solder resist layer andbefore the forming of the first open part of the first surface treatingarea and the first open part of the second surface treating area,removing the solder resist layer based on a thickness direction of asubstrate by performing the exposing and developing processes on theoverall surface of an upper portion of the solder resist layer toarbitrarily reduce a thickness thereof.
 11. The method as set forth inclaim 9, further comprising: after the forming of the solder resistlayer and before the forming of the first open part of the first surfacetreating area and the first open part of the second surface treatingarea, removing the solder resist layer based on a thickness direction ofa substrate by performing the laser machining on the overall surface ofan upper portion of the solder resist layer to arbitrarily reduce athickness thereof.
 12. The method as set forth in claim 9, furthercomprising: after the forming of the first surface treating layer andbefore the forming of the second open part of the second surfacetreating area, forming a mask layer having an open part corresponding tothe second open part of the second surface treating area on the solderresist layer.
 13. The method as set forth in claim 12, wherein the masklayer is formed of a dry film.
 14. The method as set forth in claim 9,wherein in the forming of the step open part of the first surfacetreating area, the step open part of the first surface treating area isformed so as to expose an upper surface and a side of the circuit layerof the first surface treating area.
 15. The method as set forth in claim9, wherein in the forming of the second open part of the second surfacetreating area, the second open part of the second surface treating areais formed to be equal to a size of the first open part of the secondsurface treating area based on a length direction of the substrate. 16.The method as set forth in claim 9, wherein in the forming of the secondopen part of the second surface treating area, the second open part ofthe second surface treating area is formed to be smaller than a size ofthe first open part of the second surface treating area based on alength direction of the substrate.
 17. The method as set forth in claim9, further comprising: after the forming of the step opening part of thefirst surface treating area and before the forming of the first surfacetreating layer on the exposed circuit layer of the first surfacetreating area, performing a desmear process on the step open part of thefirst surface treating area.
 18. The method as set forth in claim 9,further comprising: after the forming of the second opening part of thesecond surface treating area and before the forming of the secondsurface treating layer on the exposed circuit layer of the secondsurface treating area, performing a desmear process on the first openpart and the second open part of the second surface treating area.